Strange behaviour when recording Physics to IPO...

I’ve made a chain of boxes linked together with rigid body joints…

As I am lazy, I duplicated two boxes to make the other elements of the chain.

OOOOOOOOO <— my chain yeah…

Launched a simulation and my little chain goes as predicted…

Ok. Nice. Now I want to export the ipo to use out of the Game Engine.

The simulation run smoothly.

But when I exit the game engine, #BAM# some of the elements have changed their initial position at frame 1… They are superimposed to their parents (and sometime the parents are superimposed to their duplicate)

OOO------OO <— my chain after IPO record… gaaah!

:frowning: Can somebody tell me how I can avoid that? Or if it it an icky bug I should report?

Did you add them all in the same view (check axis orientations) and did you Ctrl-A them all?

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From what you are describing, it sounds like some of the objects are sharing IPO’s, probably a result of the duplication. This would especially be the case if the object already had an IPO assigned to it before you did the duplicating (even if it was a blank IPO).

I would recommend that you assign a separate, blank IPO to each object in the chain before running the simulation. No guarantees, but I’m pretty sure that should do the trick.

Let me know.

@Fligh

Did you add them all in the same view (check axis orientations) and did you Ctrl-A them all?
As I said, I duplicated them from one object. So basicaly they are all oriented the same way. And I purposefully wanted their orientation to match the rigid body joint constraint (I want an horizontal chain with X axis pointing up)

@Blendenzo
Tried. But it didn’t work.

When you record game physics, it wipes all the previous IPOs. So assigning a “0” key isn’t of much use.

It looks more like it is keeping the joints info from previous state or something…

The only solution I have found so far, is to completely finish your physic object before doing anything animation related. Once you have IPO keys, you are pretty much f***ed up if you need to add something… Even when you erase all the IPO keys before launching the GE again… That’s what I found strange… :frowning: